On Tuesday the FSA was granted court injunctions against accounting firms Dobb White & Co and Morris White & Co, which have offices in Leicester and Nottingham, and against two partners of both firms.
The injunctions, which will continue until trial or further order of the court, restrain the firms from undertaking any financial services business and freeze their assets.
The FSA said in a statement: "Our evidence suggests that [the firms] and [partners] Mr Gangar and Mr White have not confined themselves to accountancy, but have been running what appears to be an unlawful investment scheme that has probably taken substantially in excess of $18 million from the public."
The investigation is led by the Leicester Constabulary Economic Crime Unit on behalf of the Serious Fraud Office. It is noted that the FSA began proceedings in 1998, as a result of which Dobb White & Co and the two partners were ordered by the High Court not to accept deposits from the public.